The 31-year-old singer announced the news on Twitter Tuesday, posting a picture of the baby's hand and revealing his name to be Isaiah Michael Fisher.
Tiny hands and tiny feet...God has blessed us with an amazing gift! Isaiah Michael Fisher - born February 27. pic.twitter.com/Rxq9HUmS7W— Carrie Underwood (@carrieunderwood) March 3, 2015
Underwood and Fisher, a forward for the Nashville Predators, were married in 2010. This is the couple's first child.